Years before everyone was apparently a generalist, you would have a separate DBA, a separate architect, sometimes even separate teams for implementing algorithm

Years before everyone was apparently a generalist, you would have a separate DBA, a separate architect, sometimes even separate teams for implementing algorithms, etc. The mythical man month has a very nice section on splitting up the work over the various teams and that's a book written in the early 70s. I think the actual boundary lies more in big vs small companies: small companies do not have the resources to hire specialists for every little subproblem, while big companies typically have enough employees that specialisation becomes a possibility.